The invention relates generally to underlayment compositions and constructions and methods for reducing sounds transmission, particularly through flooring systems.
Sound rated or floating floor systems can be used in locations where it is desirable to decrease noise transmission, such as noise caused by sound vibration that travels from one area to another or impacts such as pedestrian footfalls, sports activities, dropping of toys, and/or scraping caused by moving furniture.
Sound insulation between, e.g., living areas in multi-family or single-family dwellings, is an important issue for the floor covering industry. When evaluating flooring underlayment for sound deadening characteristics; acoustical consultants, architects/specifiers and others often rely on sound testing to define the performance of a floor, ceiling or other assemblies and determine how well they insulate against noise created by impact and by airborne and other vibrations.
At least two types of laboratory sound tests performed in a controlled environment are recognized by the International Building Code (IBC) for sound vibration that travels from one living area to another: Impact Insulation Class (IIC) and Sound Transmission Class (STC). IIC tests the ability to block impact sound by measuring the resistance to transmission of impact noise or structure-borne noise (simulating footfalls, objects dropped on the floor, etc.). STC evaluates the ability of a specific construction assembly to reduce airborne sounds, such as voices, stereo systems, and TV. Both tests involve a standardized noise making apparatus in an upper chamber and a sound measuring system in a lower chamber. Decibel measurements are taken at various specified frequencies in the lower chamber. Those readings are then mathematically combined to create a whole number representation value of the test. The higher the number, the higher the resistance to sound transmission.
Non-laboratory, “field” tests for impact sound (FIIC) and for airborne sound (FSTC) are also recognized by the International Building Code. These sound tests can utilize the same or similar testing methods as IIC and STC, but are conducted in an actual building after the floor installation is completed.
Improved materials, systems and methods for reducing sound transmission and producing sound rated floors and flooring installations and systems with improved noise reduction and/or other advantages are desirable.